Balance of Payments
Current Account
current account = trade balance + services + transfers
Trade Balance
Services
Transfers
Capital Account
Statistical Discrepancy
Official Reserve Transactions
You must first understand some accounting. The current account is defined as net exports plus services plus transfers. The capital account is net purchases by foreigners of domestic assets. The remaining items are the statistical discrepancy and official reserve transactions. The net of all these things must be zero.
References
Balance of
Payments,
Herbert Stein, Concise Encyclopedia of Economics.
Balance of Payments,
Wikipedia.